Mechanical Engineering - Steam Nozzles and Turbines - Discussion

15. 

In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be

[A]. 160/3 m/s
[B]. 320/3 m/s
[C]. 640/3 m/s
[D]. 640 m/s

Answer: Option C

Explanation:

No answer description available for this question.

Tapan Majumder said: (Nov 28, 2013)  
Blade velocity = v(1)*cos(alpfa).

v1 = steam velocity at the exit of the nozzle.

v1 = 320/cos(30) = 640/(root3).

Abhi said: (Jul 27, 2017)  
U/v = cos α for reaction turbine (parson).

Raju said: (Sep 19, 2017)  
Explain the answer clearly.

Rupesh said: (Dec 9, 2018)  
u/v=cos α so u has value 320; α= 30.
320/v= cos 30.
V=640/√3.

Nitesh Bharti said: (Apr 11, 2020)  
Here it is said that exit velocity of rotor, not nozzle so Option B is correct.

Biprojit said: (Apr 25, 2020)  
Stream velocity at exit of rotor =Vr (2) = V1 and vane angle at outlet = inlet nozzle angle according to conditions of 50% rxn turbine.

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